161 



A vote of thanks to Professor Lowne for his admirable paper was proposed 

 by the Chairman, and unanimously carried. 



Mr. T. F. Smith read his paper "On Diatom Structure, ' which he illus- 

 trated by a number of choice specimens, exhibited under microscopes in the 

 room. 



The Chairman said that the criticisms which Mr. Smith had offered in the 

 course of his paper were no doubt quite capable of being answered by those 

 whose views had been opposed. Diatom structure was undoubtedly extremely 

 complicated, and where, as in these cases, the conditions of observation gave 

 rise to questions of considerable difficulty, they naturally led to differences 

 of opinion, which were by no means lessened by the way which people had 

 of seeing what they wanted to see. 



Mr. E. M. Nelson thought they had enjoyed a great treat that evening by 

 having a diatom paper from a new source ; to him, certainly, it was a great 

 pleasure to welcome a new worker in a field which was admittedly so 

 surrounded with difficulties. To get a proper notion of diatom structure 

 was important from a botanical point of view, but not less so as affording 

 the means of determining the correct interpretation of microscopic images, 

 because in all cases they were met with questions of dioptric difficulty. 

 They bad-far too few workers in this very interesting and important field. 

 As to his remarks upon Asteroniphalus, Mr. Smith was perfectly right to 

 criticise the paper as he had done, because it was certainly misleading on 

 account of its not being clearly stated that it intentionally dealt with 

 the finer structure only. The writers were perfectly conversant with the eye- 

 spots, but did not render this plain, and the matter was further complicated 

 by the wording of the paper, which ought really to have had the second 

 paper tacked on to it. He did not wonder, therefore, that Mr. Smith thought 

 they had gone wrong. The specimen which Mr. Smith was showing under 

 the name of Coscinodiscus centralis was really not centralis, but conscirms, 

 a totally different form from centralis, in which the bar cuts right through 

 the middle. The next one was quite new to him. The next was an extremely 

 beautiful specimen of Triceratium, and he thought he might say it was the 

 finest he had ever seen ; they were quite agreed as to the structure of this. 

 In Aulacodiscus Kittonii he had seen the eye-spots, and he should be happy 

 to show Mr. Smith anything which he had, and to work out the subject 

 together for the good of science. The diatom namers seemed to go rather 

 by the shapes than by structural differences ; the slide of centralis which he 

 had was one which had been very carefully and independently named. 

 Personally he felt very much obliged to Mr. Smith for his paper, and for the 

 many beautiful specimens with which he had illustrated it. 



Mr. Morland said he had been looking at some of Mr. Smith's slides, and 

 could say that the one called centralis was really Coscinodiscus hiangulatus ; 

 it was so called because where the edges turned over there Avere two angles 

 formed ; centralis was much finer. It would be found in Smith's " Atlas of 

 the Diatomacea?," and also in " Castracane on the ' Challenger ' diatoms." 



Mr. Karop said he was very pleased indeed to have heard Mr. Smith's 

 paper, which was one which ought to give rise to a good deal of discussion. 



